Low birthweight is a major determinant of neonatal mortality. It is also a significant factor affecting post neonatal mortality and infant and childhood morbidity. Black newborns are more than twice as likely to weigh less than 2,500 g as white infants. Fetal growth is influenced by many factors including the availability of trace metals. Zinc is a cofactor for several key enzymes required for DNA synthesis. Marginal zinc status is reported to be relatively common in otherwise well nourished adults. In our indigent black pregnant population, about 25% have low serum zinc (<70 ug/100ml). Theoretically, therefore, poor maternal zinc status could lead to impaired DNA synthesis and decreased fetal growth. Our preliminary studies and those of others have shown a strong relationship between low maternal zinc and decreased fetal growth, even after controlling for other factors known to affect fetal growth. Zinc deficiency, which has been associated with low birthweight, poor fetal growth and preterm delivery, may affect a large number of pregnant women, particularly of lower socioeconomic status. We propose a randomized double-blinded trial to evaluate the effect of zinc supplementation on pregnancy outcome. Two levels of zinc supplementation or a placebo will be given daily beginning at 16-18 weeks of gestation in low zinc nutriture but otherwise healthy black women who attend health department prenatal clinics. Patient compliance, indices of zinc status, and a profile of nutrients known to influence zinc status will be evaluated. We will measure plasma, leukocyte and erythrocyte zinc, serum alkaline phosphatase activity, albumin, copper, iron, and retinol binding protein, plasma and erythrocyte folate, hemoglobin and hematocrit every six weeks from enrollment until delivery. At the 16-18 week and 32 week visits a 24 hour dietary recall will be administered to compare the energy, zinc, and other nutrient intakes of volunteers. Sequential ultrasound examinations will be performed to determine pattern of fetal growth. The newborn assessment will include gestational age, birthweight, length, Apgar scores, and other newborn anthropometric measurements. Risk factors known to influence fetal growth, including pregnancy induced hypertension, diabetes, smoking history, alcohol and drug consumption, maternal weight, weight gain, and height, and other factors known to influence fetal growth will also be evaluated and correlated with maternal zinc nutriture.